Machine for recording and reproducing sound magnetically



March 21, 1939. L. s. WALLIS 2,151,629 MACHINE FOR RECORDING ANDREPRODUCING SOUND MAGNETICALLY Filled Jan. s, 19:58 SStxeets-Sheet 1March 1939- L. s. WALLIS 2,151,629

' MACHINE FDR RECORDING AND REPRODUCING SOUND MAGNETICALLY' Filed Jan.8, 1938 s sheets-sh t 2 March 21, 1939.

L. s. WALLIS 2,151,629

MACHINE FOR RECORDING AND REPRQDUCING SOUND MAGNETICALLY Filed Jan. 8,1938 5 Shets-Sheet 3 Patented Mar. 21, 1939' I umreo STATES PATENTOFFICE MACHINE FOR RECORDING AND REPRO- DUCING SOUND MAGNETICALLY LionelSelby'Wallis, Knowle, England Application January s, 1938, Serial no.184,055

In Great Britain January 9, 1937 14 Claims.

reverse or rewind a reel or spool before the record can be repeated orused again.

In these magnetic recording and reproducing 15 machines as hithertoproposed the wire is wound on a cylindrical reel or drum and is fed offunder tension through the recorder or reproducer on to a second'reel ordrum, one or both of the reels or drums being driven, or a uniformlydriven drum with which the wire record is in frictional contact isintroduced'into the feed of the wire from one reel through the recorderor reproducer to a second reel. Since the wire is hard and has aconsiderable degree of resilience it cannot be fed smoothly on to or offfrom an ordinary cylindrical reel or drum, and jerky movements of the,

-' wire are liable to take place with consequent distortion of therecording or reproduc'tion; overlapping and entangling of the coils ofthe wire 30 may also occur and necessitates stopping the machine andrewinding the wire.

With the objects .of the invention in viewI combine in a recordingandreproducing machine a stepped or relieved drum which, or the greater- 35part of which is of frusto-conical or equivalent form, on to which thewire may be wound without any of these difljlculties. This drum may beused in combination with a. second drum of like construction in amachine in which the wire record 40 is wound backwardly and forwardlyfrom drum to drum, similarly to existing machines; or I may arrange theimproved construction of drum so that the wire is fed from it throughthe recorder or reproducer andback on to the drum in a continuous mannerwithout any rewinding or reversing. i

The improved winding and feeding arrangements for a. machine of thecharacter described so are illustrated in the appended drawings inwhich: f

Figure 1 is a sectional view of'the drum for the winding and feeding of.the wire record, in its casing.

Figure 2 is a plan of the base plate of the casing of the drum. 1 VFigure 3 is a fragmentary elevation of a portion of the periphery of anattachment plate or bed plate on which the drum casing is secured. 60Figure 4 is an elevation of a sleeve.

. part oi? which a ball or roller bearing ring 34 Figure 5 is a plan ofa, wire tensloning guide arm.

Figure 6 is a diagrammatic view of the machine in which the single drumworks in a continuous manner. e 5 Figure 7 is a diagrammatic view inwhich two drums of the improved construction are used on somewhatsimilar lines to existing machines.

Figure 8 is a detail view of a joint for the ends. of the wires for usewhen the drum is used as in 10 Figure 6. 1

Figure!)- is a diagrammatic illustration of a modified form, as comparedwith the disclosure of Fig- 6.

In these drawings I0 is a drum of the preferred construction accordingto the invention,

Ii represents'the wire on which the record is made, l2 representsdiagrammatically the electrovmagnetic sound recording or reproducingdevice which may be of any suitable construction known to be effectivein this art, and I3 is a guiding and tensioning pulley for the wire.

The drum I0 is similar in outline tothe drum used in wire drawingmachines and sometimes known as a drawing block. It has; a flange M; a

portion lb of major diameter and slightly tapered adjacent to thisflange, which portion first re- I ceives the wire II as it is wound onto the drum,

then a step or abrupt change of diameter I6 and a main body part II alsoslightly tapered with a flange l8 at its smaller end.

. The drum III is enclosed in a casing comprising a domed box part l9secured bymeans of screws at 20 into a flanged bottom plate 2| which hasa bayonet connection at 22 with a fixed bed plate 23.. The flange 14 atthe base of the drum runs just within an annular wall 24 on the plate H'of the casing which wall finishes level with the upper edge of theflange which is tapered to lead the wire onto the receiving part ii ofthe drum.

A guide passage 25 cored in a boss 26 of the outer wall of the plate llof the casing leads the wire into the casing exactly tangential to thepart of maximum diameter of the receiving part l5 of the drum just abovethe flange ll.

The'drum has a hollow boss 21 to receive a bearing and above this is alead into a part 28 of square cross section or other keying sectionwhich is to form a driving connection with a complementarily shaped end29 of a shaft 30 driven by an electric motor (not shown) or ina'nysuitable manner. The shaft 30 is. conveniently'made a running fit ina sleeve 32 around -which is fitted a plain or other bearing 38 in thehollow boss 21 of the drum and onthirlower is a push fit, the outerelement of whichring is" secured in second hollow boss 38 on the drum bya spring. ring or like means 30. 'The' bearing sleeve 32 is held to thefixed base plate 2| oi' the o casing by a nut member 3'! locking itscylindrical lower part in the boss 38.

To take ofi the wire again from the drum, the wire is led oil from theupper end of the drum through a bell-mouthed bore in a hardened steelbush 39 mounted axially in the upper end of the casing.

When the wire is to be taken off from the drum to the recording orreproducing device and returned to the drum, it is desirable to apply acontrolled tension to the wire as it leaves the drum.

For this purpose, the wire as it leaves the drum is taken through ahardened steel bush 4! mounted in the outer end of an arm 40. The arm 40is rotatably mounted on a shortspindle 42 extending axially from acollar 43 secured by screws 44 to the upper end of the drum and the armis frictionally coupled to the drum by arranging it between fibre orlike washers 45 and providing a compression spring 46 on the spindle 42above the arm. The arm thus tends to rotate with the drum but isnormally held against rotation by the pull of the wire passing throughthe bush 4|. If any slack develops in the wire between the drum and therecording or reproducing device, the arm swings around with the drumthrough a sufiicient angle to take up the slack instantly sothat thewire is kept under a substantially uniform tension.

The drum is driven at a constant speed and as the wire II is alwaysbeing wound on to a constant diameter on the receiving part l5 of thedrum it is always winding at a speed which. is uniform as far as thewinding apparatus is concerned. That is to say there is no change ofdiameter due to the wire winding on to the drum in layers withconstantly increasing diameter. Owing to the short receiving part ISwith the relieved part or step 5 the wire winds smoothly thereon for afew turns and passes upwardly on to the part of less diameter in theform of a loose coil.

The method of obtaining continuous operation of the wire record from asingle drum is shown diagrammatically in Figure 6.

The ends of the wire are joined together as, for example, by a smallball or bead 48 and the wire leaving the upper end of the drum is guidedextending between the openings in the drum When winding thewireinitially on the drum, several turns of the wire are first woundaround the wire-receiving part of the drum and the free .end is broughtout through the bush 38 in. the upper end of the casing. The drum isthen rotated to wind the rest of the wire on to it and the free endsoutside the casing are joined. It is found in practice that if severalturns of the wire are wound initially by hand around the wirereceivingpart of the drum, there is no need to connect any part of the wire tothe drum.

If desired, advantage can be taken of the junction of the ends of thewire to operate a switch for stopping the record automatically at agiven point. The ball or bead 48 can be made to engage in a shaped fork49 of a spring blade or' movable lever arm 50 and rock that over as therecord travels thus operating through suitable connections a switch inthe circuit of the motor which drives the drum. If desired the samemeans may apply a brake to the drum.

Whilst the continuous winding and taking off on the same drum ispreferred, the drum l0 may be fed from any convenient form of reel ordrum or from a second drum of like form as shown in Figure '7. Inthiscase the wire is attached at one end to one drum'il and at its otherend to the second drum 5!. After passing through the recording orreproducing apparatus [2 (see Fig. 6) the wire H is wound on to the drum5!. After completion of the record the drums can be changed over on tothe driving spindle or means may be provided for detachably connectingeach drum to a driving means.

In the arrangement illustrated in Figure 1 by disconnecting the bayonetjoint between the casing and the bed plate 23 the drum and its casingcan be bodily lifted off the driving spindle 30 and another drum withits record can be placed thereon.

If desired the wire may be stored on and fed ofi from an ordinary realor the like, and as the wire is fed smoothly on to the drum ill beyondthe recording or reproducing device and tension is applied to the wirebetween the reel and that device irregularities in the feeding of thewire off the reel do not afiect the uniformity of its movement throughthe recording or reproducing device. With this arrangement the wireafter use can be wound back on to the reel for storage.

I claim: v

1. The combination in a machine for recording and reproducing soundmagnetically by means of a magnetically energized wire, of a driven drumhaving. a relatively short wire-receiving part on to which the wire iswound and having an abruptly stepped reduction in diameter between thiswire receiving part and a body part around which the wire forms in aloose coil, said body part tapering away from said step or change ofdiameter.

2. The combination in a machine for recording and reproducing soundmagnetically by means of a wire record, of a'drum having a flange orend, a relatively short portion of the drum periphery of .major diameteradjacent to the flange, and a main drum part of smaller diameter andtapering away from said flange or end, said main drum part beingabruptly stepped inwardly from said relatively short part. i

3. The combination in a machine for recording and reproducing soundmagnetically by means of a wirerecord, of a driven drum having awirereceiving part and a main body part, a step in diameter between saidwire receiving part and said body part and said body part tapering awayfrom said step, a fixed casing around said drum and a guide opening insaid casing leading the wire on to the said wire-receiving part of thedrum.

4. The combination in a machine for recording and reproducing soundmagnetically by means of a wire record, of a driven drum having awirereceiving part and a main body part, a step in diameter between saidwire-receiving part and K said body part and said body part taperingaway be wound, driving means therefor, electro-magnetic sound recordingor reproducing means through which said wire record is fed, tensioningmeans for the wire record as it is fed to the recording or reproducingmeans, and tensioning means for said record as it is carried to themeans on which it is wound; the means on which the record is woundincluding a drum having an abrupt inward step between the part whichfirst receives the wire, and the main part of the drum, which main partis of less diameter than said smaller diameter, the body part taperingaway from the st p; a rotatable shaft for driving the drum, a casing forthe drum in two parts ineluding a bed plate with a bearing for the drumbeing continuously fed from and to the magnetic and a box part enclosingthe drum with a quickly detachable connection between the box part andthe bed plate and a sliding driving connection between said shaft andsaid drum, whereby the casing may be bodily removed with said drum fromsaid bed plate and'changed.

'7. The combination in a machine for recording sound magnetically bymeans 01' a wire record, of a drum having a wire-receiving part and amain body part and a step down in diameter from the wire-receiving partto the main body part, the main body part tapering away from said step,a casing around the drum and a drivshaft entering the casing and havinga driving connection with the drum; a guide opening in said casing forthe wire record through which the wire is led on to the wire-receivingpart of the drum, and a guide arm floating with respect to the drum butsuitably loaded so that it will guide the wire as it is fed oil theopposite end of the drum to the receiving part and will apply tension tothe wire.

8. A machine for recording sound magnetically by means of a wire recordcomprising in combination a drum on to which the wire is wound said drumhaving a wire-receiving part of major diameter and a main part, aboutwhich the wire record becomes loosely coiled, of smaller diameter andtapering from said wire-receiving part, a driving means for the drum andmeans for guiding and applying tension to the wire record as it is fedfrom the smaller end of the drum; a magnetic recording or reproducingdevice from whichthewirerecordisiedtosaiddrumanda guiding and tensioningpulley around which" said wire record whereby during recording orreproducingthe record the wire record is being continuously wound on, tothe one end or the driven drum and at the same time ted oi! from theother end or said drum.

9. In a'machine for recording or reproducing sound magneticallyby meansof a wire record,.

the combination of a single driven means comprlsingasteppeddrumon tothelarger end of which the wire record is being woundcontinuously and fromthe smaller end or which it is sound recording or reproducing meansduring the recording or reproducing process, with means for guiding saidwire record and applying tensiontosaidrecoldbetwemitsi'eedingoflpclnton- V 2,151,132) comprising meanson which the wire record can said drum and the polntjat' which it iswound thereon. V

10. In a machine for recordmg or reproducing sound magnetically by meansof a wire record the combination or a driven drum having a shortwire-receiving part which is slightly tapered and a tapered body part ofsmaller diameter on to which the wire passes from the wire-receivingpart, there being an abrupt inward step between said wire-receiving partand said body part.

1']. In a machine for recording or reproducing sound magnetically bymeans oi a wire record the combination of a magnetic recording orreproducing device, means for feeding a wire record through said device,means for maintaining a constant tension in said wire, a rotating drumon to which the wire passes from said recording or reproducing device,and means for driving said drum at a constant speed, said drum having anannular surface on to which said wire is wound and a body part abruptlystepped inwardly of the annular surface and of smaller diameter on towhich the wire passes from said annular surface and on which said wiremay be stored.

12. In a. machine iorrecording or reproducing sound magnetically bymeans of a wire record the combination of a magnetic recordingforreproducing device, means for feeding a wire record-through saiddevice, means for maintaining. a constant tension in said wire, a drumon to which said wire passes from saidrecording or reproducing device,means for driving said drum at a constant speed, said drum having anannular surface on to which said wire is wound and a body part ofsmaller diameter on to which the wire passes from said annular surface,a stop on said wire, a movable member through which the wire can pass,and a control actuated by the movable member when it is engaged by thestop on the wire to discontinue the drive for the drum and also ifdesired to apply a brake to the drum.

13. In a machine for recording or reproducing sound magnetically bymeans of a wire record the combination of asingle driven meanscomprising a stepped drum on to the larger end of which the wire recordis fed from a magnetic sound recording or reproducing device and fromthe smaller end or which the wire is led to said device, means forguiding said wire and applying tension to it between the points at whichit is fed on to and taken oi! Item the drum, a stop on said wire, amovable member through which said wire can pass freely. and controlmeans actuated by said movable member whereby when the stop engages saidmember the drive for the drum is discontinued and drum if desired isbraked.

14. In a machine for recording or reproducing sound magnetically bymeans of a wire record, the combination of a driven drum on to which thewire is wound, said drum having a wire .re-

celving part of major diameter and a main part of smaller diameter andtapering from said wire receiving part, an endless wire record, a meansfor guiding and applying tension to the wire record as it is fed fromthe smaller end of the drum, a magnetic recording or reproducing vdevicefrom which the record is fed to said drum. and guiding and tensioningmeans for said wire record whereby during recording or reproducing therecord the wire is being continuously wound ontooneendofthedrumand'atthesametime i'edofliromtheotherendofsaiddrum.

- LIONEL SKI-BY WALLIS.

